Apparatus for producing



G. s. MIEIKLE Re. 20,939

APPARATUS FOR PRODUCING COMBUSTION Original Filed April 26, 1927 2Sheets-Sheet 1 V inventor- Z 1933' G. s. MEIKLE Re. 20,939

APPARATUS FOR PRODUCING COMBUSTION I Original Fi lqd April 26, 1927 2sheets-sheet 2 Rciuued Dec. 6, 1938 UNITED STATES APPARATUS FORPRODUCING CODIBUSTION George Stanley Meikle, West Lafayette, Ind.

Original No. 1,856,720, dated May 3, 1932, Serial No. 186,625, April 26,1927. Application for reissue April 30, 1934, Serial No. 723,279

14 Claims.

This invention relates to apparatus for efiecting combustion of liquidfuels.

More particularly, this invention relates to apparatus for effecting thecombustion of liquid hydrocarbons in the combustion chamber of ordinarydomestic furnaces.

The object of the invention is to provide suitable apparatus foreffecting improved combustion of liquid hydrocarbon fuels wherebycombustion of relatively high eiilciency results, giving a bluish flamethat is substantially smokeless.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the features of construction,combinations of elements,

and'arrangement of parts, which will be exem.

plifled in the constructions hereinafter set forth and the scope of theapplication of which will be indicated in the claims.

For a.fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

Fig. 1 is a fragmentary view, mainly in section, with parts broken awayshowing a burner installed in a domestic furnace for the practice of thepresent invention;

Fig. 2 is a similar view, showing a modified arrangement for thepractice of the presentinvention; v

Fig. 3 is a view showing in elevation a detail of the burner top shownin Fig. 2;

Fig. 4 is" a horizontal sectional view through. theburner top shown inFig. 3;

Fig. 5 is an explanatory diagram showing the manner in which parts ofthe burner top function; and r Fig. 6 is a view partly in section andpartly in elevation showing another modified form of burner forpracticing the present invention.

Referring now to the drawings, and particularly to Fig. 1, III denotes awater-leg of an ordinary domestic furnace'which extends. downwardly toform one wall of the combustion chamber, The water-leg I0 is supportedupon a. base which may comprise and is here shown as the ash pit for thefurnace. A burner I2, whicl. extends upwardly into the combustionchamber from the ash pit, has a base l3, and is of suiiicient height toenable it Just to project above a layer offlre brick II which forms ahearth that'is disposed snugly between thebase l3 and the lower edge ofthe water-leg In so as to close off completely the bottom of thecombustion chamber in an airtight manner. The base ii of the burner isshown supported on suitable lugs ii that rest on the floor or othersupport in the ash pit.

The burner is'of a type adapted for burning liquid hydrocarbon fuels,and to this end has one or more fuel-feeding nozzles I6 extendingupwardly through the base, each having an outwardly turned tip l1 fromwhich there issues a spray or Jet of the liquid hydrocarbon fuel. Inorder that this spray or jet may "be properly atomized, and mixed withthe air for combustion purposes, the burner is provided with a rotatinghead It, the head being driven at a relatively high rate of rotation byany suitable "means, for example, by a directly coupled electric motoras shown at l9.

v The nozzles ii are adapted to discharge into a plurality of tubularpassages 20 disposed in an annulus on the under side of the head l8.These discharge tubes have a diameter so proportioned to the nozzles l6and are disposed such distance therefrom that there is an entrainingaction for air as the nozzles 16 discharge thereinto.

When the head l8 rotates, it is seen that a centrifugal force operatesto accelerate the passage of the mixed air and hydrocarbon fuel in thepassages 20 in an outward radial direction. In order, however, that themixture which issues from the passages 20 shall be more thoroughlyatomized and "mixed with air for combustion, the issuing mixture is,made to pass through a series of conical bailies, here shown at 2|, 22and 23. These baflles are nested, and. by reason of this arrangement,project slightly into each other successively, so that when the head isrotating they entrain additional air, by the injector principle, as thecombustible mixture passes through the same. In order that the airsupply to the burner may be regulated, the base I! is shown as providedwith a sliding member 24 which may be partially rotated about thevertical axis of the burner in order to operate as a shutter forcontrolling the air supply. Provision to force fuel jets to issue fromthe nozzles l6, can be made 45 in any convenient manner; for exampleybythe hydrostatic pressure of a constant head of fuel under gravity feed(not shown here in the interest of clearness).

The burner head I 8 is rotated at a velocity sufiicient to project thecombustible mixture a considerable distance beyond the rim of the headbefore it has had time to ignite. In a given in stallation, this mixtureaccumulates and ignition takes place adjacent the water-leg II. To Ifacilitate combustion at this place, fillet-like refractory blocks 25are disposed upon the hearth ll about the circumference thereof adjacentthe water-leg. These blocks do not flt snugly down on the hearth nortight against the water-leg but are spaced some distance away from each.The fillet-blocks 25 are accordingly shown as having supporting ledges26 extending downwardly therefrom onto the hearth supporting the I same,and providing base passages 21 which extend to the rear and communicateby vertical channels 21' with the combustion chamber. In operation, itis thus seen that the function of the burner head when rotating is tosupply in highly atomized condition, a combustible mixture in multi-jetform and to project it horizontally with sufflcient velocity thatignition takes place some distance from, rather than at, the rim of theburner head, or in other words, the velocity of the combustible mixtureis in excess of the velocity of flame propagation.

Here the hearth and the refractory fillet-blocks cooperate with theburner in a manner quite different from that heretofore practiced in thecombustion art, and provide the means for carrying out an important stepin the practice of the method of the present invention. The average jetof atomized mixture, as it approaches the illet-blocks, follows thearrow at a and is drawn under and about the same, rising into thecombustion chamber as indicated-by the arrows b and c. In this regionthe principal part of the combustion takes place, heating the walls ofthe water-leg and also the hearth and refractory fillet-blocks. The heatabsorbed by these refractories is not lost, as it is radiated away, butis utilized in increasing the efliciency of the com-- bustion. (Thatradiated to the water-leg is utilized in heating the water as usual.)The heat radiated inwardly by the refractories is seen to be radiatedagainst the advance of the let-like mixture. Consequently as it advancesover the hearth toward the water-leg, it becomes subjected to a heatingeffect of increasing intensity until it flnally bursts into flame on andunder the fillet-blocks. The heating zone through which the sheet-likecombustible mixture passes, when thus traversed by radiant heat, reactsto crack the hydrocarbon fuel and cause a partial union between it andthe oxygen contained in the air supplied for supporting combustion. Thisunion may be other than a full chemical union and may he, therefore,termed an oxygenation process, so that when the Jets of combustiblemixture finally reach the heated refractories at 25, the mixturecontains substantially only the most volatile hydrocarbons intimatelyassociated with oxygen and will not be disintegrated by contact with'thewater-leg "into free carbon: The flame, in consequence of this cracking,is very stable-and burns as a bluish flame, without soot, at the. wallsof the water-leg where the 'heat evolved is quickly abmrbed.

By reason of the intimate mixing of air and atomized fuel, which iseffected in theburner head when rotating, and by reason 'of the partialoxygenation that takes place when the jets of combustible mixturetraverse the heating zone, substantially complete combustion takes.place in the flame at the water-leg, without the presence of any excessair. As a consequence a combustion process is had in which highefliciencies are attained. The placing of the flame against thewater=leg results in such complete abmrption of heat from the gasesduring combustion, that the flue gases escaping from the combustionchamber have a relatively low stack temperature, as well as contain onlysubstantially the correct ratio of carbon dioxide gas to the neutralgases.

By the arrangement of the burner head cen-' trally with respect to thehearth, over which the jets of combustible mixture are projected, acirculation of the products of combustion iseifected within thecombustion chamber which also contributes to the efliciency of thepresent process of combustion. By reference to Fig. 1, it is seen thatthe column of gas standing directly over the burnerhead 18 has its lowerend agitated by the rotation of the burner head and in consequence hasits particles thrown radially outward from points above the rim ofthe'head, as indicated by the arroyv d. This action creates a downwardsuction in the gas column over the centre of the burner head, with aradial movement outwardly over the multi-jet mixture, which moving bodyof gas again moves upwardly adjacent the flame on the water-leg and,after rising therewith a certain distance, is again drawn toward thecentre and downwardly by the suction of the central column of gas. Thismotion of the gas may be briefly termed a vortex motion; it results incontinuous internal circulation of heated products of combustion. Suchcirculation in turn results in the equalization of the temperature ofthe burnervhead with that of the products of combustion, and inenveloping the jets of combustible mixture projected from the burner onboth sides by heating agents; on their lower side they are adjacent thehearth, while their upper side is covered by the circulating body 'ofgas. The circulating body of gas serves to pro-, tect the burner, and tosome extent,diifuses with" the jets of combustible mixture, and while ata relatively high temperature, by reason of its passage through the zoneof the intense radiated heat adjacent to the flame, yet assists inpreventing ignition until the water-leg is reached. This diffusionresults in applying some of the remnantheat in the products ofcombustion, carried away from the flame on the walls of the water-leg,to

the initial heating and acceleration of the partial oxygenation of theJets of combustible mixture.

The manner in which the present invention operates is thus seen toinvolve a succession of steps by which a combustible mixture is causedto issue in an atomized state from a burner oriflce at such a velocitythat combustion does not take place immediately at the oriflce; in thenext step,

the atomized particles in the combustible are thereafter vaporized,partially omenized and cracked by heat imparted from heat-storing,bodies such as the hearth and the body of gas executing the vortexmovement. "In thesucceeding step the vaporized and cracked mixture ismixed with the heated product of combustion, preventing ignition untilit is raised to a kindling temperature substantially at a surface of thebody which it is desired to heat.

In the modified arrangement shown in Fig.

all of the air for the combustible mixture is not supplied by theentering. action of the atomized fuel issuing from the burner nozzle,but is blown into the same by external means. Here a burner head 28 hasa driven shaft 2! for rotating it and is provided with vertical picktubes 30 which supply a spray of atomized fuel to localized points onthe'wall of the bumer-cup in a manner hereinafter more fully described.It will beseen that thereisaloeal regionoftheburner-cupwallon? andissues from the annular ,orifice 32 to en-' counter baffles 33 as itpasses radially out from the annular orifice where it is further brokenup and mixed with air. Anexternal blower 34 has pipe connections 35feeding an annular air trunk 36 which is adapted to supply one or morestreams of air through pipes 36 for combustion purposes to the jets ofcombustible mixture that pass tangentially thereover. These jets, thisadmixed with air, travel over the heated hearth 31 and finally impingeon the refractory struc- .ture 38 disposed about the periphery of thehearth snugly adjacent to the water-leg Ill. The refractory structureshown comprises a plurality of relatively narrow steps between which aredisposed grooves 39, having obliquely inclined smooth bottoms as shown.For round domestic boilers, this refractory structure may be made in theform of stepped bricks somewhat curved so that they may be placedend-to-end as segments of an arc. ,In this form the steps may be cutback from the ends of the bricks to provide the grooved passages 33.Each brick may be so formed as to provide passages only at its ends, ormay have one or more extending crosswise of its length forming groovesin the body thereof.

The stepped, structure here employed is in lieu of the fillet-blocksshown in Fig. 1. The oblique passages operate to divert upwardly theimpinging jets, as well as the steps. They also operate to impart acertain amount of dispersion to the radiant heat reflected inwardlytoward the burn- In this manner a relatively deep heatingzone isprovided which is traversed by jets of combustible mixture projectedfrom the burner head 23, issuing in vertical banks.

Where the burner head has relatively deep bailies, as those at 33,extending over the hearth adjacent to the burner, these baflles not onlyoperate to impart motion to the combustible mixture, but operate also toset in motion the under strata air or gas lying directly upon the hearthbeneath the jets of combustible mixture. This setting in motion isaccomplished by the centrifugal force acting on the body of air or gasabout the baiiies. The radial movement of the body causes an upwardsuction lifting the air or gas directly from the hearth. .These resultsin con- 1 sequence a vortex movement of the smaller body lit) oLgasdirectly beneath the projected jets of combustible mixture similar tothe one above produced as described in connection with Fig. 1, exceptthat its direction of rotation in radial planes is in the oppositedirection. This lower vortex assists in conveying some heat to the jetsof combustible mixture but assists principally in supplying further airfor combustion and in the process of oxygenation.

These baiiles 33, if made relatively deep, will set arelatively largebody of gas in motion beneath the jets of combustible mixture. It isdesirable in consequence to limit the bailies both in number and indepth. They are accordingly not disposed uniformly about the under sideof the head, but are disposed preferably only about.

limited segmental orifices as indicated in Fig. 3. Here the head 23 hastwo segmental orifices 39 disposed on opposite sides of the head, eachorifice having a limited number of baffles 33. This will more clearlyappear by reference to Fig. 4. These baiiies, however, are not disposedalong radial lines, since it is desired that they should cooperate inatomizing the spray of fuel oil that issues from the tops of thepick-tubes 33, but on tangents to a,circle shown at S.

The trajectory traversed by a particle of spray from a pick-tube 3D isdiagrammatically shown in Fig. 5, where the curve is drawnrelative tothe burner cup. The particle starts at e to move radially outward fromthe tube 30, under theiniiuence of centrifugal force. This particlecontinues moving radially outward from the tube, as it turns away. (Inthe drawings the direction of rotation here assumed is clockwise and isindicated by the arrow placed above the plan of the head.) The particlein consequence appears to veer to the left relative to the tube 30. Theparticle. during this movement accelerates outwardly until it strikesthe side of the burner cup, indicated in the sketch at point I. Here itslides under its own inertia along the side of the cup and upwardlyuntil it moves radially out over the lip 3|. The portion of the curvepassing over the lip is denoted When the particle leaves the lip 3|, itis again free to travel in space outwardly. At this point, however, itis desirable to dispose a bailie 33 in its path to intercept its travelbut arranged to interpose relatively little resistance. This involvesthe angular disposition shown for the baiiie. Its path on the baiiie isindicated at h.

In case the particle had a velocity such that it left the lip of the cupat a point later in the cycle of rotation than shown, its radialvelocity would, of course be diiferent when it left the lip and thebaflles 33 at such points would have a correspondingly different angulardisposition with respect to the radii. This is clearly shown in Fig. 4.The particle, when it leaves the battle 33, is again permitted toaccelerate in free space and traces the backwardly curved trajectorydenoted at k.

The path of the particle here traced may be the path of a single globuleof fuel oil, or it may be the path of amere geometrical particle whichdenotes the average path of the atomized bodies that result from asingle globule which issues from the tube 30. Such a globule, when itarrives vat I generally becomes flattened into a thin film of oil on theside of the cup and coalesces with other globules on the side of thespherical shape but become flattened by the resistance of the air intooblate ellipsoids with their shortest axis lying in the direction oftravel.

The flattening action upon the fuel globules produced by the highvelocities here employed have been ascertained to be beneficial to theprocess of combustion here practiced, since the globules thereby exposea greater surface subheat radiated from refractory structure in theheating zone.

If it should be desired to employ the baille structure shown at 33 inthe burner head, and yet suppress the vortex motion of the lower body ofgas so that'the projected combustible mixture may come more closely incontact with the hearth as in Fig. 1, this may be accomplished by themodified arrangement shown in Fig. 6. Here the burner head 28 is mountedon a burner cup 40 which is surrounded by a burner casing 4! projectingup into the combustion chamber and so formed with a flange 42 disposedto project outwardly to the edge of the rim of the burner head so thatsuction on the body of air or gas in the combustion chamber directlybeneath the jets of combustible mixture is substantially cut off.

In the arrangement shown the suction induced by the baiiles 33 (notshown in Fig. 6) on head It draws air in from an air chamber 63 providedin the burner casing as a draft chamber for furnishing air forcombustion both through the holes ll in the bottom of the burner cup andthrough an annular passage 45 about the burner cup. The latter airsupply is generally termed "secondary air", since it is not incorporatedin the first instance in the fuel mixture that is formed in the burnercup, but is later admixed by the bailies 33. The first incorporated airis generally termed primary air.

It is preferable to regulate the air supplied in this manner other thanby the velocity of rotation imparted to the head. Hence a circular airfro damper 4G is shown for controlling the air admitted through passages41 to the air chamber 43. This damper is provided with any convenientmeans for adjusting it vertically up and down; for example with themanually actuated stud It.

By this arrangement the primary and secondary air are simultaneouslycontrolled. It is not essential to do this however, since means may beprovided for controlling either the primary or secondary airindependently.

Depending from the air chamber is theoil well easing "into which thepick-tubes 3O depend in order to raise an oil spray therefrom by theprinciple of relative velocities, as set forth in Letters Patent of theUnited States 1,624,350

issued April 5, 1926, in the name of H. D. Mac- Kaye and myself, towhich reference should be had for a fuller understanding of theoperation of the parts here conventionally shown.

In this arrangement, which is adapted to effect a more complete initialatomization of the fuel than with the first described arrangement, thecombustible mixture passing over the hearth is cracked and vaporized byheat supplied by the hearthand the superincumbentbody of gas insubstantially the same manner as set forth above.v

Since certain changes in carrying out the con struction set forth, whichembody the invention may be made without departing from its scope, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrativeandstantially normally to the influence of the radiant jected at arelatively high velocity, refractory heat storage means disposedcooperatively adjacent said head op'er which said projected mix turepasses, and means disposed at some distance from said head for reducingthe velocity of said mixture whereby a blue flame combustion 'of saidmixture is eil'ected substantially at said means.

2. In a burner structure, the combination with a rotatable head havingmeans for ejecting jets of liquid fuel, of impacting means for atomizingsaid jets, means associated with said atomizing means for entraining airto form a combustible mixture, said head being provided with an orificethrough which said mixture is projected at a relatively high velocity, arefractory heat storage body disposed cooperatively adjacent the saidhead and arranged to heat the projected mixture passing thereover andmeans disposed on said body at some distance from said head for reducingthe velocity of said mixture, whereby a blue flame combustion of saidmixture is effected at a surface to be heated, disposed adjacently tosaid means.

3. In a burner structure, the combination with a rotatable head having afuel ejecting nozzle structure associated therewith for emitting jets ofliquid hydrocarbon fuel, of a baille structure carried by said head foratomizing said jets, means cooperatively associated with said head foradmixing air with said atomized fuel to. form a combustible mixture,said head being formed to project said combustible mixture by therotation of said head-at a relatively high velocity to- .ward a surfaceto' be heated, and heat-storage bodies cooperatively disposed betweensaid bumer and said surface toward which said mixture is projected,whereby the hydrocarbon component of said mixture is cracked andvaporized to effect a blue-flame combustion at the surface to be heated.

4. In a burner structure, the combination with a rotatable head having afuel-ejecting nozzle associated therewith for emitting jets of liquidhydrocarbon fuel, of a bailie structure disposed on said head foratomizing the fuel emitted in said jets, means associated therewith foren-' training air to form a combustible mixture, said head being formedwith openings through which.

said mixture is projected radially at a relatively high velocity towarda surface to be heated, and refractory heat-storage bodies disposed insubstantially air'tight relation between said burner and said surface,whereby said projected mixture passes over said bodies and thehydrocarbon component of said mixture is cracked and vaporized, andwhereby a blue flame combustion is effected substantially at the surfaceto be heated.

5. In a burner structure, the combination with a rotatable head havingfuel feeding means and a rotatable open cup' adapted toupartiallyatomize a liquid hydrocarbon fuel fed thereto and fuel ejecting. nomlesadapted for rotation with said cup for emitting jets of the partiallyatomized liquid hydrocarbon fuel flowing from said cup, of

means in said head for further atomizing said its passage over the arotatable open cup and means for supplying fuel. thereto, said cuphaving means for emitting streams of air and partially atomized liquidhydrocarbon fuel, of a depending baille structure disposed about theperiphery of said cup, comprising a plurality of blades disposed insubstantially vertical planes slightly inclined to the radii of saidcup, said blades being in the path of said streams and adapted to admixadditional air therewith and to effect further atomization of the fuel,and power means for rotating said cup.

7. In a burner structure, the, combination with a rotatable burner cupprovided with means for emitting streams of liquid hydrocarbon fuel, ofa cap-plate secured to said cup having blades disposed about theperiphery of said cap-plate in planes substantially at right angles tothe plane of said cap-plate, said planes being slightly inclined to theradii of said cap-plate, said blades depending fromsaid cap-plate andarranged both to atomize by-impact said streams of fuel and to impel airfor combustion, and power means for rotating said cup.

8. A burner unit including a centrifugal distributing head rotatablymounted with respect to a furnace, said head including a rotatable opencup having radial fuel supply tubes secured thereto to discharge aplurality of partially atomized streams ofa liquid hydrocarbon fuel,means for feeding a liquid hydrocarbon fuel to said cup, a fan elementfixed to said head and having vanes extending above and below thedischarge ends of said tubes'and disposed radially outside said ends.

9. In a. burner structure, the combination with a rotatable headprovided with nozzles for emitting jets of liquid hydrocarbon fuel, ofimpacting means on said head for atomizing said jets, baflie meansassociated with said atomizing means for entraining air by the passageof said jets to form a combustible mixture, said head being formed withpassages through which said mixture is projected radially at a velocityin excess of that of flame propagation toward a surface to be heated, ahearth cooperatively disposed between said burner structure and thesurface to be heated in a substantially-airtight manner, and means onsaid hearth at a distance from said head for reducing the velocity ofthe combustible mixture to and extent whereby when said mixture hasreached said surface, it becomes ignited and a substantially blue flamecombustion results.

10. In a burner structure, the combination with a rotatable head havingfuel ejecting nozzles associatedtherewith for emitting jets of liquidhydrocarbon fuel, of impacting means in said head for atomizing saidjets, baflle means associatedwith the first said means for admixing airwith said atomized fuel, a hearth cooperatively disposed about saidburner structure beneath the path of said atomized fuel and extending toa surface to be heated, and refractory means on said hearth disposedabout the periphery thereof in the path of combustion whereby radiantheat is supplied to the heating zone above said hearth.

11. In a burner structure, the combination with tory means being in thepath of the products of combustion whereby it becomeshighly heated andsupplies radiant heat to the atomized fuel.

12. In-a burner structure, the combination with a rotatable head havingfuel ejecting, nozzles associated therewith for emitting jets of liquidhydrocarbon fuel, of impacting means in said head for atomizing saidjets, baflie means associated with the first saidmeans for admixing airwith said atomized fuel, a hearth cooperatively disposed about saidburner structure beneath the path of said atomized fuel and extendingto-a surface to be heated, means for supplying additional air to saidatomized fuel during its'passage over said hearth, and refractory meanson said hearth disposed about the periphery thereof for supplyingradiant heat to the heating zone above said hearth which is traversed bythe atomized fuel.

13. An oil burner, having a rotatable head comprising a rotatableannular trough, a plurality oftubular passages secured thereto forrotation therewith and projecting outwardly therefrom, a plurality ofrotary fan blades disposed adjacent the discharge ends of said tubularpassages, and a stationary oil feeding tube-connected with a source ofoil supply and having a discharge end terminating adjacent said annulartrough.

14. An oil burner adapted for mounting in a combustion chamber andcomprising a rotatable annular trough and aplurality of tubular passagessecured thereto for rotation therewith, a rotatable fan rotatable withsaid trough and having blades adjacent said tubular passages, astationary oil supply member adapted to-supply oil to said tubue 'lar'passages, and driving mechanism connected with and adapted to rotatesaid trough and fan at a predetermined speed whereby oil admixed withair is thrown outwardly of said tubular passages and into the combustionchamber at a velocity in excess of the rate. of flame propagation.

GEORGE STANLEY MEIKIE.

